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De Angelis M, Schobesberger S, Selinger F, Sedlmayr VL, Frauenlob M, Corcione O, Dong S, Gilardi G, Ertl P, Sadeghi SJ. A multi-channel microfluidic platform based on human flavin-containing monooxygenase 3 for personalised medicine. RSC Adv 2024; 14:13209-13217. [PMID: 38655484 PMCID: PMC11037025 DOI: 10.1039/d4ra01516a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 04/16/2024] [Indexed: 04/26/2024] Open
Abstract
Human flavin-containing monooxygenase 3 (FMO3) is a drug-metabolizing enzyme (DME) which is known to be highly polymorphic. Some of its polymorphic variants are associated with inter-individual differences that contribute to drug response. In order to measure these differences, the implementation of a quick and efficient in vitro assay is highly desirable. To this end, in this work a microfluidic immobilized enzyme reactor (μ-IMER) was developed with four separate serpentines where FMO3 and its two common polymorphic variants (V257M and E158K) were covalently immobilized via glutaraldehyde cross-linking in the presence of a polylysine coating. Computational fluid dynamics simulations were performed to calculate the selected substrate retention time in serpentines with different surface areas at various flow rates. The oxidation of tamoxifen, an anti-breast cancer drug, was used as a model reaction to characterize the new device in terms of available surface area for immobilization, channel coating, and applied flow rate. The highest amount of product was obtained when applying a 10 μL min-1 flow rate on polylysine-coated serpentines with a surface area of 90 mm2 each. Moreover, these conditions were used to test the device as a multi-enzymatic platform by simultaneously assessing the conversion of tamoxifen by FMO3 and its two polymorphic variants immobilized on different serpentines of the same chip. The results obtained demonstrate that the differences observed in the conversion of tamoxifen within the chip are similar to those already published (E158K > WT > V257M). Therefore, this microfluidic platform provides a feasible option for fabricating devices for personalised medicine.
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Affiliation(s)
- Melissa De Angelis
- Department of Life Sciences and Systems Biology, University of Torino via Accademia Albertina 13 10123 Torino Italy
| | | | - Florian Selinger
- TU Wien, Faculty of Technical Chemistry Getreidemarkt 9 1060 Vienna Austria
| | | | - Martin Frauenlob
- TU Wien, Faculty of Technical Chemistry Getreidemarkt 9 1060 Vienna Austria
| | - Orsola Corcione
- Department of Life Sciences and Systems Biology, University of Torino via Accademia Albertina 13 10123 Torino Italy
| | - Shiman Dong
- Department of Life Sciences and Systems Biology, University of Torino via Accademia Albertina 13 10123 Torino Italy
| | - Gianfranco Gilardi
- Department of Life Sciences and Systems Biology, University of Torino via Accademia Albertina 13 10123 Torino Italy
| | - Peter Ertl
- TU Wien, Faculty of Technical Chemistry Getreidemarkt 9 1060 Vienna Austria
| | - Sheila J Sadeghi
- Department of Life Sciences and Systems Biology, University of Torino via Accademia Albertina 13 10123 Torino Italy
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2
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Gasteazoro F, Catucci G, Barbieri L, De Angelis M, Dalla Costa A, Sadeghi SJ, Gilardi G, Valetti F. Cascade reactions with two non-physiological partners for NAD(P)H regeneration via renewable hydrogen. Biotechnol J 2024; 19:e2300567. [PMID: 38581100 DOI: 10.1002/biot.202300567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 03/14/2024] [Accepted: 03/15/2024] [Indexed: 04/08/2024]
Abstract
An attractive application of hydrogenases, combined with the availability of cheap and renewable hydrogen (i.e., from solar and wind powered electrolysis or from recycled wastes), is the production of high-value electron-rich intermediates such as reduced nicotinamide adenine dinucleotides. Here, the capability of a very robust and oxygen-resilient [FeFe]-hydrogenase (CbA5H) from Clostridium beijerinckii SM10, previously identified in our group, combined with a reductase (BMR) from Bacillus megaterium (now reclassified as Priestia megaterium) was tested. The system shows a good stability and it was demonstrated to reach up to 28 ± 2 nmol NADPH regenerated s-1 mg of hydrogenase-1 (i.e., 1.68 ± 0.12 U mg-1, TOF: 126 ± 9 min-1) and 0.46 ± 0.04 nmol NADH regenerated s-1 mg of hydrogenase-1 (i.e., 0.028 ± 0.002 U mg-1, TOF: 2.1 ± 0.2 min-1), meaning up to 74 mg of NADPH and 1.23 mg of NADH produced per hour by a system involving 1 mg of CbA5H. The TOF is comparable with similar systems based on hydrogen as regenerating molecule for NADPH, but the system is first of its kind as for the [FeFe]-hydrogenase and the non-physiological partners used. As a proof of concept a cascade reaction involving CbA5H, BMR and a mutant BVMO from Acinetobacter radioresistens able to oxidize indole is presented. The data show how the cascade can be exploited for indigo production and multiple reaction cycles can be sustained using the regenerated NADPH.
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Affiliation(s)
- Francisco Gasteazoro
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
- CICATA Unidad Morelos, Instituto Politécnico Nacional, Mexico D. F., Mexico
| | - Gianluca Catucci
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | - Lisa Barbieri
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
- University School for Advanced Studies IUSS Pavia, Pavia, Italy
| | - Melissa De Angelis
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | | | - Sheila J Sadeghi
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | - Gianfranco Gilardi
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | - Francesca Valetti
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
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3
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Shi T, Sun X, Yuan Q, Wang J, Shen X. Exploring the role of flavin-dependent monooxygenases in the biosynthesis of aromatic compounds. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:46. [PMID: 38520003 PMCID: PMC10958861 DOI: 10.1186/s13068-024-02490-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 03/13/2024] [Indexed: 03/25/2024]
Abstract
Hydroxylated aromatic compounds exhibit exceptional biological activities. In the biosynthesis of these compounds, three types of hydroxylases are commonly employed: cytochrome P450 (CYP450), pterin-dependent monooxygenase (PDM), and flavin-dependent monooxygenase (FDM). Among these, FDM is a preferred choice due to its small molecular weight, stable expression in both prokaryotic and eukaryotic fermentation systems, and a relatively high concentration of necessary cofactors. However, the catalytic efficiency of many FDMs falls short of meeting the demands of large-scale production. Additionally, challenges arise from the limited availability of cofactors and compatibility issues among enzyme components. Recently, significant progress has been achieved in improving its catalytic efficiency, but have not yet detailed and informative viewed so far. Therefore, this review emphasizes the advancements in FDMs for the biosynthesis of hydroxylated aromatic compounds and presents a summary of three strategies aimed at enhancing their catalytic efficiency: (a) Developing efficient enzyme mutants through protein engineering; (b) enhancing the supply and rapid circulation of critical cofactors; (c) facilitating cofactors delivery for enhancing FDMs catalytic efficiency. Furthermore, the current challenges and further perspectives on improving catalytic efficiency of FDMs are also discussed.
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Affiliation(s)
- Tong Shi
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China
| | - Xinxiao Sun
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China
| | - Qipeng Yuan
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China
| | - Jia Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China.
| | - Xiaolin Shen
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China.
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Cárdenas-Moreno Y, González-Bacerio J, García Arellano H, Del Monte-Martínez A. Oxidoreductase enzymes: Characteristics, applications, and challenges as a biocatalyst. Biotechnol Appl Biochem 2023; 70:2108-2135. [PMID: 37753743 DOI: 10.1002/bab.2513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 09/03/2023] [Indexed: 09/28/2023]
Abstract
Oxidoreductases are enzymes with distinctive characteristics that favor their use in different areas, such as agriculture, environmental management, medicine, and analytical chemistry. Among these enzymes, oxidases, dehydrogenases, peroxidases, and oxygenases are very interesting. Because their substrate diversity, they can be used in different biocatalytic processes by homogeneous and heterogeneous catalysis. Immobilization of these enzymes has favored their use in the solution of different biotechnological problems, with a notable increase in the study and optimization of this technology in the last years. In this review, the main structural and catalytical features of oxidoreductases, their substrate specificity, immobilization, and usage in biocatalytic processes, such as bioconversion, bioremediation, and biosensors obtainment, are presented.
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Affiliation(s)
- Yosberto Cárdenas-Moreno
- Laboratory for Enzyme Technology, Centre for Protein Studies, Faculty of Biology, University of Havana, Havana, Cuba
| | - Jorge González-Bacerio
- Laboratory for Enzyme Technology, Centre for Protein Studies, Faculty of Biology, University of Havana, Havana, Cuba
- Department of Biochemistry, Faculty of Biology, University of Havana, Havana, Cuba
| | - Humberto García Arellano
- Department of Environmental Sciences, Division of Health and Biological Sciences, Metropolitan Autonomous University, Lerma, Mexico, Mexico
| | - Alberto Del Monte-Martínez
- Laboratory for Enzyme Technology, Centre for Protein Studies, Faculty of Biology, University of Havana, Havana, Cuba
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Catucci G, Turella S, Cheropkina H, De Angelis M, Gilardi G, Sadeghi SJ. Green production of indigo and indirubin by an engineered Baeyer–Villiger monooxygenase. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2022. [DOI: 10.1016/j.bcab.2022.102458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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6
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Reis RAG, Li H, Johnson M, Sobrado P. New frontiers in flavin-dependent monooxygenases. Arch Biochem Biophys 2021; 699:108765. [PMID: 33460580 DOI: 10.1016/j.abb.2021.108765] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 12/15/2022]
Abstract
Flavin-dependent monooxygenases catalyze a wide variety of redox reactions in important biological processes and are responsible for the synthesis of highly complex natural products. Although much has been learned about FMO chemistry in the last ~80 years of research, several aspects of the reactions catalyzed by these enzymes remain unknown. In this review, we summarize recent advancements in the flavin-dependent monooxygenase field including aspects of flavin dynamics, formation and stabilization of reactive species, and the hydroxylation mechanism. Novel catalysis of flavin-dependent N-oxidases involving consecutive oxidations of amines to generate oximes or nitrones is presented and the biological relevance of the products is discussed. In addition, the activity of some FMOs have been shown to be essential for the virulence of several human pathogens. We also discuss the biomedical relevance of FMOs in antibiotic resistance and the efforts to identify inhibitors against some members of this important and growing family enzymes.
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Affiliation(s)
| | - Hao Li
- Department of Biochemistry, Blacksburg, VA, 24061, USA
| | - Maxim Johnson
- Department of Biochemistry, Blacksburg, VA, 24061, USA
| | - Pablo Sobrado
- Department of Biochemistry, Blacksburg, VA, 24061, USA; Center for Drug Discovery, Virginia Tech, Blacksburg, VA, 24061, USA.
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7
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Catucci G, Aramini D, Sadeghi SJ, Gilardi G. Ligand stabilization and effect on unfolding by polymorphism in human flavin-containing monooxygenase 3. Int J Biol Macromol 2020; 162:1484-1493. [PMID: 32781122 DOI: 10.1016/j.ijbiomac.2020.08.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/24/2020] [Accepted: 08/04/2020] [Indexed: 12/20/2022]
Abstract
Pharmacogenomics is a powerful tool to prevent adverse reactions caused by different response of individuals to drug administration. Single nucleotide polymorphisms (SNPs) represent up to 90% of genetic variations among individuals. Drug metabolizing enzymes are highly polymorphic therefore the kinetic parameters of their catalytic reactions can be significantly influenced. This work reports on the unfolding process of a phase I drug metabolizing enzyme, human flavin-containing monooxygenase 3 (hFMO3) and its single nucleotide polymorphic variants (SNPs) V257M, E158K and E308G. Differential scanning calorimetry (DSC) indicates that the thermal denaturation of the enzyme is irreversible. The melting temperature (Tm) for the (Wild Type) WT and its polymorphic variants is found to be in a range from 46 °C to 50 °C. Also the activation energies of unfolding (Ea) show no significant differences among all proteins investigated (290-328 KJ/mol), except for the E308G variant that showed a significantly higher Ea of 412 KJ/mol. The presence of the bound NADP+ cofactor is found to stabilize all the variants by shifting the main Tm by 4-5 °C for all the proteins, exception made for E308G where no changes are observed. Isothermal titration calorimetry (ITC) was used to characterize the interaction of the protein with NADP+ in terms of dissociation constant (Kd), enthalpy (ΔH) and entropy (ΔS). Kd values of 1.6 and 0.7 μM, ΔH of -13.9 Kcal/mol and -16.8 Kcal/mol, ΔS of -20.5 cal/mol/deg, and -28.5 cal/mol/deg were found for V257M and E158K respectively. E308G was found to be unable to bind the NADP+ cofactor, a result that is in line with the Tm results. Circular dichroism also confirmed an overall lower stability of E308G, while NADP+ was found to give a strong positive shift of the Tm stabilizing the structure of E158K (46.2 to 50.6 °C). Previous data highlighted significant differences in terms of activity among the SNPs of hFMO3. In this work a minor impact of the SNPs was found on the stability of the enzyme in the ligand free form, except for E308G, whereas the binding of NADP+ reveals major differences among WT and polymorphic variants that are all measurable in terms of heat capacity, enthalpy and secondary structure content. These data provide the first direct evidence of ligand stabilization effects on hFMO3 that can explain the differences observed in catalytic efficiencies and serve as the starting point for the development of inhibitors of this enzyme.
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Affiliation(s)
- G Catucci
- Department of Life Sciences and Systems Biology, University of Torino, Italy
| | - D Aramini
- Department of Life Sciences and Systems Biology, University of Torino, Italy
| | - S J Sadeghi
- Department of Life Sciences and Systems Biology, University of Torino, Italy
| | - G Gilardi
- Department of Life Sciences and Systems Biology, University of Torino, Italy.
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8
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Natural Variation in the ‘Control Loop’ of BVMOAFL210 and Its Influence on Regioselectivity and Sulfoxidation. Catalysts 2020. [DOI: 10.3390/catal10030339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Baeyer-Villiger monooxygenases (BVMOs) are flavin-dependent enzymes that primarily convert ketones to esters, but can also catalyze heteroatom oxidation. Several structural studies have highlighted the importance of the ‘control loop’ in BVMOs, which adopts different conformations during catalysis. Central to the ‘control loop’ is a conserved tryptophan that has been implicated in NADP(H) binding. BVMOAFL210 from Aspergillus flavus, however, contains a threonine in the equivalent position. Here, we report the structure of BVMOAFL210 in complex with NADP+ in both the ‘open’ and ‘closed’ conformations. In neither conformation does Thr513 contact the NADP+. Although mutagenesis of Thr513 did not significantly alter the substrate scope, changes in peroxyflavin stability and reaction rates were observed. Mutation of this position also brought about changes in the regio- and enantioselectivity of the enzyme. Moreover, lower rates of overoxidation during sulfoxidation of thioanisole were also observed.
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9
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Abstract
Flavin-dependent monooxygenases (FMOs) are ancient enzymes present in all kingdoms of life. FMOs typically catalyze the incorporation of an oxygen atom from molecular oxygen into small molecules. To date, the majority of functional characterization studies have been performed on mammalian, fungal and bacterial FMOs, showing that they play fundamental roles in drug and xenobiotic metabolism. By contrast, our understanding of FMOs across the plant kingdom is very limited, despite plants possessing far greater FMO diversity compared to both bacteria and other multicellular organisms. Here, we review the progress of plant FMO research, with a focus on FMO diversity and functionality. Significantly, of the FMOs characterized to date, they all perform oxygenation reactions that are crucial steps within hormone metabolism, pathogen resistance, signaling and chemical defense. This demonstrates the fundamental role FMOs have within plant metabolism, and presents significant opportunities for future research pursuits and downstream applications.
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10
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Ciaramella A, Catucci G, Di Nardo G, Sadeghi SJ, Gilardi G. Peroxide-driven catalysis of the heme domain of A. radioresistens cytochrome P450 116B5 for sustainable aromatic rings oxidation and drug metabolites production. N Biotechnol 2020; 54:71-79. [DOI: 10.1016/j.nbt.2019.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 08/22/2019] [Accepted: 08/23/2019] [Indexed: 02/08/2023]
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Abstract
Trimethylamine N-Oxide (TMAO) is the product of the monooxygenation reaction catalyzed by a drug-metabolizing enzyme, human flavin-containing monooxygenase 3 (hFMO3), and its animal orthologues. For several years, researchers have looked at TMAO and hFMO3 as two distinct molecules playing specific but separate roles, the former to defend saltwater animals from osmotic or hydrostatic stress and the latter to process xenobiotics in men. The presence of high levels of plasmatic TMAO in elasmobranchs and other animals was demonstrated a long time ago, whereas the actual physiological role of hFMO3 is still unknown because the enzyme has been mainly characterized for its ability to oxidize drugs. Recently TMAO was found to be related to several human health conditions such as atherosclerosis, cardiovascular, and renal diseases. This correlation poses a striking question of how other vertebrates (and invertebrates) can survive in the presence of very high TMAO concentrations (micromolar in humans, millimolar in marine mammals and several hundred millimolar in elasmobranchs). Therefore, it is important to address how TMAO, its precursors, and FMO catalytic activity are interconnected.
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Catucci G, Gao C, Rampolla G, Gilardi G, Sadeghi SJ. Uncoupled human flavin-containing monooxygenase 3 releases superoxide radical in addition to hydrogen peroxide. Free Radic Biol Med 2019; 145:250-255. [PMID: 31580948 DOI: 10.1016/j.freeradbiomed.2019.09.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/26/2019] [Accepted: 09/29/2019] [Indexed: 11/21/2022]
Abstract
Human flavin-containing monooxygenase 3 (hFMO3) is a drug-metabolizing enzyme capable of performing N- or S-oxidation using the C4a-hydroperoxy intermediate. In this work, we employ both wild type hFMO3 as well as an active site polymorphic variant (N61S) to unravel the uncoupling reactions in the catalytic cycle of this enzyme. We demonstrate that in addition to H2O2 this enzyme also produces superoxide anion radicals as its uncoupling products. The level of uncoupling was found to vary between 50 and 70% (WT) and 90-98% (N61S) for incubations with NADPH and benzydamine over a period of 5 or 20 min, respectively. For the first time, we were able to follow the production of the superoxide radical in hFMO3, which was found to account for 13-18% of the total uncoupling of this human enzyme. Moreover, measurements in the presence or absence of the substrate show that the substrate lowers the level of uncoupling only related to the H2O2 and not the superoxide radical. This is consistent with the entry point of the substrate in this enzyme's catalytic cycle. These findings highlight the importance of the involvement of hFMO3 in the production of radicals in the endoplasmic reticulum, as well as the relevance of single-nucleotide polymorphism leading to deleterious effects of oxidative stress.
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Affiliation(s)
- Gianluca Catucci
- Department of Life Sciences and Systems Biology, University of Torino, Italy
| | - Chongliang Gao
- Department of Life Sciences and Systems Biology, University of Torino, Italy
| | - Giulia Rampolla
- Department of Life Sciences and Systems Biology, University of Torino, Italy
| | - Gianfranco Gilardi
- Department of Life Sciences and Systems Biology, University of Torino, Italy
| | - Sheila J Sadeghi
- Department of Life Sciences and Systems Biology, University of Torino, Italy.
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Fürst MJLJ, Gran-Scheuch A, Aalbers FS, Fraaije MW. Baeyer–Villiger Monooxygenases: Tunable Oxidative Biocatalysts. ACS Catal 2019. [DOI: 10.1021/acscatal.9b03396] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Maximilian J. L. J. Fürst
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, Groningen 9747AG, The Netherlands
| | - Alejandro Gran-Scheuch
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, Groningen 9747AG, The Netherlands
- Department of Chemical and Bioprocesses Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Santiago 7820436, Chile
| | - Friso S. Aalbers
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, Groningen 9747AG, The Netherlands
| | - Marco W. Fraaije
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, Groningen 9747AG, The Netherlands
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Efficient Synthesis of Methyl 3-Acetoxypropionate by a Newly Identified Baeyer-Villiger Monooxygenase. Appl Environ Microbiol 2019; 85:AEM.00239-19. [PMID: 30926727 DOI: 10.1128/aem.00239-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 03/24/2019] [Indexed: 11/20/2022] Open
Abstract
Baeyer-Villiger monooxygenases (BVMOs) are an emerging class of promising biocatalysts for the oxidation of ketones to prepare corresponding esters or lactones. Although many BVMOs have been reported, the development of highly efficient enzymes for use in industrial applications is desirable. In this work, we identified a BVMO from Rhodococcus pyridinivorans (BVMORp) with a high affinity toward aliphatic methyl ketones (Km < 3.0 μM). The enzyme was highly soluble and relatively stable, with a half-life of 23 h at 30°C and pH 7.5. The most effective substrate discovered so far is 2-hexanone (k cat = 2.1 s-1; Km = 1.5 μM). Furthermore, BVMORp exhibited excellent regioselectivity toward most aliphatic ketones, preferentially forming typical (i.e., normal) products. Using the newly identified BVMORp as the catalyst, a high concentration (26.0 g/liter; 200 mM) of methyl levulinate was completely converted to methyl 3-acetoxypropionate after 4 h, with a space-time yield of 5.4 g liter-1 h-1 Thus, BVMORp is a promising biocatalyst for the synthesis of 3-hydroxypropionate from readily available biobased levulinate to replace the conventional fermentation.IMPORTANCE BVMOs are emerging as a green alternative to traditional oxidants in the BV oxidation of ketones. Although many BVMOs are discovered and used in organic synthesis, few are really applied in industry, especially in the case of aliphatic ketones. Herein, a highly soluble and relatively stable monooxygenase from Rhodococcus pyridinivorans (BVMORp) was identified with high activity and excellent regioselectivity toward most aliphatic ketones. BVMORp possesses unusually high substrate loading during the catalysis of the oxidation of biobased methyl levulinate to 3-hydroxypropionic acid derivatives. This study indicates that the synthesis of 3-hydroxypropionate from readily available biobased levulinate by BVMORp-catalyzed oxidation holds great promise to replace traditional fermentation.
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Tolmie C, Smit MS, Opperman DJ. Native roles of Baeyer–Villiger monooxygenases in the microbial metabolism of natural compounds. Nat Prod Rep 2019; 36:326-353. [DOI: 10.1039/c8np00054a] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Baeyer–Villiger monooxygenases function in the primary metabolism of atypical carbon sources, as well as the synthesis of complex microbial metabolites.
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Affiliation(s)
- Carmien Tolmie
- Department of Biotechnology
- University of the Free State
- Bloemfontein
- South Africa
| | - Martha S. Smit
- Department of Biotechnology
- University of the Free State
- Bloemfontein
- South Africa
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16
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Binding of methimazole and NADP(H) to human FMO3: In vitro and in silico studies. Int J Biol Macromol 2018; 118:460-468. [PMID: 29959003 DOI: 10.1016/j.ijbiomac.2018.06.104] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 06/06/2018] [Accepted: 06/22/2018] [Indexed: 01/10/2023]
Abstract
Human flavin-containing monooxygenase isoform 3 (hFMO3) is an important hepatic drug-metabolizing enzyme, catalyzing the monooxygenation of nucleophilic heteroatom-containing xenobiotics. Based on the structure of bacterial FMO, it is proposed that a conserved asparagine is involved in both NADP(H) and substrate binding. In order to explore the role of this amino acid in hFMO3, two mutants were constructed. In the case of N61Q, increasing the steric hindrance above the flavin N5-C4a causes poor NADP(H) binding, destabilizing the catalytic FAD intermediate, whereas the introduction of a negatively charged residue, N61D, interferes mainly with catalytic intermediate formation and its stability. To better understand the substrate-enzyme interaction, in vitro as well as in silico experiments were carried out with methimazole as substrate. Methimazole is a high-affinity substrate of hFMO3 and can competitively suppress the metabolism of other compounds. Our results demonstrate that methimazole Pi-stacks above the isoalloxazine ring of FAD in hFMO3, in a similar way to indole binding to the bacterial FMO. However, for hFMO3 indole is found to act as a non-substrate competitive inhibitor. Finally, understanding the binding mode of methimazole and indole could be advantageous for development of hFMO3 inhibitors, currently investigated as a possible treatment strategy for atherosclerosis.
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Bordewick S, Beier A, Balke K, Bornscheuer UT. Baeyer-Villiger monooxygenases from Yarrowia lipolytica catalyze preferentially sulfoxidations. Enzyme Microb Technol 2018; 109:31-42. [DOI: 10.1016/j.enzmictec.2017.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/18/2017] [Accepted: 09/19/2017] [Indexed: 12/14/2022]
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Balke K, Beier A, Bornscheuer UT. Hot spots for the protein engineering of Baeyer-Villiger monooxygenases. Biotechnol Adv 2018; 36:247-263. [DOI: 10.1016/j.biotechadv.2017.11.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/15/2017] [Accepted: 11/17/2017] [Indexed: 10/18/2022]
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Inactivation mechanism of N61S mutant of human FMO3 towards trimethylamine. Sci Rep 2017; 7:14668. [PMID: 29116146 PMCID: PMC5676948 DOI: 10.1038/s41598-017-15224-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/23/2017] [Indexed: 12/18/2022] Open
Abstract
Human flavin-containing monooxygenase 3 (hFMO3) catalyses the oxygenation of a wide variety of compounds including drugs as well as dietary compounds. It is the major hepatic enzyme involved in the production of the N-oxide of trimethylamine (TMAO) and clinical studies have uncovered a striking correlation between plasma TMAO concentration and cardiovascular disease. Certain mutations within the hFMO3 gene cause defective trimethylamine (TMA) N-oxygenation leading to trimethylaminuria (TMAU) also known as fish-odour syndrome. In this paper, the inactivation mechanism of a TMAU-causing polymorphic variant, N61S, is investigated. Transient kinetic experiments show that this variant has a > 170-fold lower NADPH binding affinity than the wild type. Thermodynamic and spectroscopic experiments reveal that the poor NADP+ binding affinity accelerates the C4a-hydroperoxyFAD intermediate decay, responsible for an unfavourable oxygen transfer to the substrate. Steady-state kinetic experiments show significantly decreased N61S catalytic activity towards other substrates; methimazole, benzydamine and tamoxifen. The in vitro data are corroborated by in silico data where compared to the wild type enzyme, a hydrogen bond required for the stabilisation of the flavin intermediate is lacking. Taken together, the data presented reveal the molecular basis for the loss of function observed in N61S mutant.
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Mthethwa KS, Kassier K, Engel J, Kara S, Smit MS, Opperman DJ. Fungal BVMOs as alternatives to cyclohexanone monooxygenase. Enzyme Microb Technol 2017; 106:11-17. [PMID: 28859804 DOI: 10.1016/j.enzmictec.2017.06.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 06/19/2017] [Accepted: 06/30/2017] [Indexed: 12/12/2022]
Abstract
FAD-dependent Baeyer-Villiger monooxygenases (BVMOs) have proven to be useful biocatalysts in the selective and specific oxygenation of various ketones. Despite the cloning, heterologous expression and characterization of close to 80 members of this enzyme family, some sub-groups of BVMOs still remain underrepresented and their evolutionary relationship uncertain. Until recently, very few fungal BVMOs have been described. Our previous investigations into BVMOs from the fungus Aspergillus flavus, yielded very little activity on simple cyclic ketones. Here we report on another four BVMOs from A. flavus that are more closely related to cyclohexanone monooxygenase (CHMO) from Acinetobacter sp. NCIMB 9871. Evolutionary analysis with other characterized BVMOs show their closest relationship to be with either cycloalkanone monooxygenase (CAMO) or 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetyl-coenzyme A monooxygenase (OTEMO). The OTEMO-related BVMOAFL706 and BVMOAFL334 were heterologously expressed in E. coli, purified and shown to be able to convert a range of cyclic and substituted cyclic ketones. Of the unsubstituted cyclic ketones, cyclohexanone showed the highest conversion with maximum turnover frequencies reaching 4.3s-1 for BVMOAFL706. Unlike CHMOacinet, and many of the closely related BVMOs, no substrate inhibition was observed with cyclohexanone to a concentration of up to 30mM, creating the possibility for applications requiring high substrate loading. Aliphatic ketones were also readily converted with excellent regioselectivity. Similar to CHMOacinet, acetophenones were not converted and the oxidation of rac-cis-bicyclo[3.2.0]hept-2-en-6-one occurs enantiodivergently, with the (1R,5S) isomer converted to the "normal" lactone and the (1S,5R) isomer to the "abnormal" lactone.
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Affiliation(s)
- Katlego Siphamandla Mthethwa
- Department of Biotechnology, University of the Free State, 205 Nelson Mandela Drive, Bloemfontein, 9300, South Africa
| | - Karin Kassier
- Department of Biotechnology, University of the Free State, 205 Nelson Mandela Drive, Bloemfontein, 9300, South Africa
| | - Jennifer Engel
- Institute of Technical Biocatalysis, Hamburg University of Technology, Denickestr. 15, Hamburg, 21073, Germany
| | - Selin Kara
- Institute of Technical Biocatalysis, Hamburg University of Technology, Denickestr. 15, Hamburg, 21073, Germany
| | - Martha Sophia Smit
- Department of Biotechnology, University of the Free State, 205 Nelson Mandela Drive, Bloemfontein, 9300, South Africa
| | - Diederik Johannes Opperman
- Department of Biotechnology, University of the Free State, 205 Nelson Mandela Drive, Bloemfontein, 9300, South Africa.
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Chemical applications of Class B flavoprotein monooxygenases. RENDICONTI LINCEI-SCIENZE FISICHE E NATURALI 2016. [DOI: 10.1007/s12210-016-0583-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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